L-Lysine
Research reviewed: Up until 03/2026
L-Lysine is a dietary supplement with 3 published peer-reviewed studies involving 3,200 participants, researched for Cold Sore (Herpes) Prevention.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Cold Sore (Herpes) Prevention
StrongResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Cold Sore (Herpes) Prevention
To assess L-lysine supplementation for recurrent herpes simplex labialis prevention.
Study Type
Randomised, double-blind, placebo-controlled crossover
Purpose
To assess L-lysine supplementation for recurrent herpes simplex labialis prevention.
Dose
L-lysine 1000mg daily (prevention) or 3000mg (treatment)
Participants
52 patients with history of recurrent herpes labialis
Duration
6 months
Results
L-lysine 1g/day significantly reduced recurrence frequency. Higher dose (3g) reduced severity and healing time of active outbreaks. Well tolerated.
How They Measured It
Herpes recurrence frequency, severity rating, healing time
To evaluate L-lysine on recurrence rate of HSV infection.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate L-lysine on recurrence rate of HSV infection.
Dose
L-lysine 1248mg daily
Participants
65 patients with recurrent herpes labialis
Duration
12 months
Results
Significant reduction in herpes recurrences and symptom severity. Mechanism involves competitive inhibition of arginine required for HSV replication.
How They Measured It
Cold sore recurrence count, symptom severity, duration
To meta-analyse L-lysine efficacy for herpes simplex virus prophylaxis.
Study Type
Meta-analysis
Purpose
To meta-analyse L-lysine efficacy for herpes simplex virus prophylaxis.
Dose
L-lysine 1000-3000mg daily
Participants
Multiple RCTs combined
Duration
Various
Results
L-lysine at doses ≥1250mg/day significantly effective for HSV recurrence prevention. Clear dose-response relationship. Lower doses (500mg) less consistently effective.
How They Measured It
Herpes recurrence rate, duration, severity across included RCTs
Frequently Asked Questions
Common questions about L-Lysine research
There are currently 55 peer-reviewed studies on L-Lysine (L-Lysine), involving 3,200 total participants. Research covers Cold sore prevention, Collagen synthesis, Immune support and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (3 human studies), and reported outcomes.
L-Lysine has been researched for: Cold sore prevention, Collagen synthesis, Immune support, Bone health. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 3 out of 55 studies are human trials. Human trials carry more weight in our evidence scoring system.
